The invention relates to heterophasic polyolefin alloys with a semi-interpenetrating network structure and an outstanding combination of high stiffness and low temperature toughness and optionally with a low coefficient of thermal expansion, consisting of propylene polymers and modified elastomers, which are suitable for the manufacture of films, sheets, fibers, panels, coatings, injection molded articles, pipes, hollow objects and foams. The invention also relates to a method for producing these heterophasic polyolefin alloys.
Thermoplastic elastomers, as heterophasic polyolefin alloys of high toughness, are known. Known elastomeric components for thermoplastic elastomers based on polypropylene are ethylene propylene elastomers (EP 672 712; EP 614 940), ethylene propylene diene elastomers (EP 547 843; EP 409 542), ethylene vinyl acetate copolymers (BE 899507; Coran, A., Rubber Chem. Technol. 54 (1981), 892), chlorosulfonated polyethylene (U.S. Pat. No. 4,141,878), elastomeric copolymers of ethylene and C4 to C8 olefins, such as elastomeric ethylene butene copolymers (Kautschuk-Gummi-Kunststoffe 49 (1996) 12, 812-813), ethylene hexene copolymers or ethylene octene copolymers (Yu, T. J. Plastic Film and Sheeting 10 (1994) 1, 539-564), as well as elastomeric atactic polypropylenes (EP:334-829) in amounts of 35 to 70% by weight, based on the polyolefin mixture.
The composition of the polyolefin components and of the elastomeric components and the distribution of the elastomeric components in the polyolefin component are of decisive significance for the material properties of heterophasic polyolefin alloys with elastomers, such as strength and elasticity (Moore, P., Polypropylene Handbook, Carl Hanser-Verlag Munich 1996, 218 to 225).
It is furthermore known that the elastomeric components in polyolefin alloys, which are based on polypropylene/ethylene propylene diene elastomers, can be vulcanized by additions, such as dodecyl mercaptan (DE 26 20 820), sulfur (EP 336 780) or tetrabutyl thiuram disulfide (EP 376 213). However, these formulations have the disadvantage of discoloring severely, so that semi-finished and molded products of these materials can be used only if they are dyed black.
Heterophasic polyolefin alloys based on polypropylene and elastomeric C4 to C8 olefins can be dyed particularly well. However, compared to heterophasic polyolefin alloys based on polypropylenes and vulcanized ethylene propylene diene elastomers, they have a significantly lower strength level.
For formulations from polypropylenes and elastomeric ethylene hexene copolymers, it is known that the blends can be modified by electron beam radiation (JP 96 301 927).
Furthermore, grafting of polyethylene as well as of ethylene copolymers with ethylenically unsaturated hydrolyzable organosilane compounds and the hydrolytic cross linking of these grafted copolymers is known (German patent 26 11 491; U.S. Pat. No. 3,646,155; British patent 1,406,680).
It is also known that the impact strength of polypropylenes can be modified by the addition of 10 to 35% by weight of amorphous ethylene propylene diene elastomers (Michaeli, W., Z. Kunststoffberater (1990) 3, 38-43; Kloos, F., Angewandte Makromolekulare Chemie 185/186 (1991), 97-108), ethylene propylene elastomers (Kim, B., J. Applied Polymer Science 60 (1996), 2207-2218, J. Applied Polymer Science 60 (1996), 1391-1403), likewise in the form of reactor blends of polypropylene and ethylene and ethylene propylene rubber (Kresge, E., Macromol. Symp. 53 (1992), 173-189, Schwager, H. Kunststoffe 82 (1992) 6, 499-501), ethylene butene elastomers (Yu, C., SPE-ANTEC 94, 2439-2442, SPE-ANTEC ""96, 1995-2000), ethylene hexene copolymers (J 08 301 927, Yamaguchi, M., J. Applied Polymer Science 63 (1997), 467-474) and ethylene octene elastomers (EP 0 769 525, J 97 48 920).
The object of the invention is to form heterophasic polyolefin alloys from propylene polymers and elastomers, which have a high stiffness, a low temperature toughness and optionally a low coefficient of thermal expansion.
Surprisingly, it was found that, by melt compounding partially cross linked blends, which were synthesized by the reaction of elastomeric polyolefins or styrene ethylene butadiene terpolymers or of mixtures of propylene polymers and elastomeric polyolefins or styrene ethylene butadiene terpolymers with ethylenically unsaturated, hydrolyzable organosilane compounds in the presence of free radical-forming agents and silanol condensation catalysts, with an excess of propylene polymers, heterophasic polyolefin alloys with a semi-interpenetrating network structure can be produced, which fulfill these requirements. At the same time, it was observed that the partially cross linked elastomeric polyolefins formed are distributed homogeneously in the polypropylene matrix as extended, filamentous network structures.
The objective of the invention was accomplished by heterophasic polyolefin alloys with a semi-interpenetrating network structure and an outstanding combination of high stiffness, low temperature toughness and optionally a low coefficient of thermal expansion, which consists of 65 to 99.6% by weight of propylene polymers and 35 to 0.4% by weight of elastomeric polyolefins or styrene ethylene butadiene terpolymers and optionally 0.01 to 2.5% by weight of stabilizers, 0.01 to 1% by weight of processing aids, 0.1 to 1% by weight of antistatic agents, 0.2 to 3% by weight of pigments, 0.05 to 1% by weight of nucleating agents and/or 2 to 20% by weight of flame retardants, in each case based on the sum of the polymers, as auxiliary materials, and/or optionally 10 to 70% by weight and preferably 20 to 50% by weight, based on the sum of the polymers, of inorganic and/or organic fillers and/or reinforcing materials, the heterophasic polyolefin alloys, pursuant to the invention, having a gel content of
GHP=10xe2x88x922CB(GB+N(100xe2x88x92GB)).
wherein
GHP=gel portion of the heterophasic polyolefin alloys in % by weight
CB=Concentration of the co-continuous blend B in the polyolefin alloy in % by weight
GB=gel portion of the co-continuous blend B in % by weight
N=post cross linking factor=0.10 to 0.90
and being prepared by melt compounding 60 to 98% by weight of conventional propylene homopolymers or propylene copolymers A with melt indexes ranging from 0.1 to 50 g/10 minutes at 230xc2x0 C./2.16 kg with 40 to 2% by weight of a co-continuous blend B, optionally with the addition of 0.01 to 0.5% by weight of silanol condensation catalysts and/or 0.01 to 0.5% of water,
and wherein the co-continuous blends B on the basis of
B1) conventional propylene polymers or propylene copolymers with melt indexes ranging from 0.1 to 50 g/10 minutes at 230xc2x0 C./2.16 kg,
which are present in the mixture in an amount of 20 to 90% by weight of the elastomeric polyolefins or elastomeric styrene ethylene butadiene terpolymers
B2) olefin copolymers of 50 to 95% by weight of ethylene and 50 to 5% by weight of propylene and/or xcex1-olefins with 4 to 18 carbon atoms and/or ethylenically unsaturated carboxylate esters of the vinyl acetate type and/or C1 to C8 alkyl (meth)acrylates with melt indexes of 0.2 to 30 g/10 minutes at 190xc2x0 C./2.16 kg, and/or
B3) largely amorphous polypropylenes or propylene copolymers with a crystalline polypropylenes or crystalline propylene copolymers content of less than 10% by weight, an enthalpy of melting of less than 40 J/g and a melt index of 0.1 to 40 g/10 minutes at 230xc2x0 C./2.16 kg, the elastomeric, largely amorphous polypropylene being a homopolymer of propylene and/or a copolymer of propylene of at least 80 mole percent propylene and not more than 20 mole percent of one or more xcex1-olefins of the general formula CH2=CHR, wherein R is a linear or branched alkyl group with 2 to 8 carbon atoms, and/or
B4) non-isotactic propylene homopolymers with a melting point of 145xc2x0 to 165xc2x0 C., a melt viscosity of more than 200,000 g/m/sec at 190xc2x0 C., a heat of crystallization of 4 to 10 cal/g and a solubility in diethyl ether of 35% by weight to 55% by weight, and/or
B5) linear styrene ethylene / butadiene styrene triblock copolymers with an ethylene content of 5 to 45% by weight and a styrene content of 15 to 45% by weight and a melt index of 0.2 to 30 g/10 minutes at 190xc2x0 C./2.16 kg,
the co-continuous blends containing 0.1 to 5.0% by weight of chemically bound, ethylenically unsaturated, hydrolyzable organosilane compounds and 5 to 60% by weight and preferably 25 to 50% by weight of gel, are synthesized
1) either by the reaction of mixtures of 10 to 80% by weight of conventional propylene homopolymers or propylene copolymers and 90 to 20% by weight of elastomeric polyolefins or styrene ethylene butadiene terpolymers with 0.1 to 5.0% by weight of ethylenically unsaturated hydrolyzable organosilane compounds in the presence of 0.01 to 1.0% by weight of thermally decomposing free radical-forming agents with half-life times of 1 minute to 48 hours at 130xc2x0 C., 0.01 to 1.0% by weight of silanol condensation catalysts and optionally 0.01 to 1.0% by weight of water, in each case based on the elastomeric polyolefins or styrene ethylene butadiene terpolymers in the melt,
2) or by the reaction of mixtures of 6 to 66% by weight of conventional propylene homopolymers or propylene copolymers and 94 to 33% by weight of elastomeric polyolefins or of styrene ethylene butadiene terpolymers with 0.1 to 5.0% by weight, based on the elastomeric polyolefins or on the styrene ethylene butadiene terpolymers of ethylenically unsaturated, hydrolyzable organosilane compounds in the presence of 0.01 to 1.0% by weight, based on the elastomeric polyolefins or on the styrene ethylene butadiene terpolymers, of thermally decomposing free radical-forming agents in the melt and the addition of a further 5 to 40% by weight, based on the polymer mixture, of conventional propylene homopolymers or propylene copolymers, and 0.01 to 1.0% by weight of silanol condensation catalysts and optionally 0.01 to 1.0% by weight of water, based in each case on the elastomeric polyolefins or styrene ethylene butadiene terpolymers, in the melt,
3) or by the reaction of elastomeric polyolefins or styrene ethylene butadiene terpolymers with 0.1 to 5.0% by weight of ethylenically, unsaturated, hydrolyzable organosilane compounds in the presence of 0.01 to 1.0% by weight, based on the elastomeric polyolefins or the styrene ethylene butadiene terpolymers, of thermally decomposing free radical-forming agents in the melt, followed by granulation and subsequently by melt compounding of mixtures of 90 to 20% by weight of these, modified, elastomeric polyolefins or styrene ethylene butadiene terpolymers and 10 to 80% by weight of conventional propylene homopolymers or propylene copolymers in the presence of 0.01 to 1.0% by weight of silanol condensation catalysts and optionally of 0.01 to 1.0% of water, based in each case on the elastomeric polyolefins or the styrene ethylene butadiene terpolymers,
and whereby the conventional propylene homopolymers or propylene copolymers A and the conventional propylene homopolymers or propylene copolymers B1) can be the same or different.
Preferably, as conventional propylene homopolymers or propylene copolymers A or B1), propylene homopolymers and/or copolymers of propylene, ethylene and/or xcex1-olefins with 4 to 18 carbon atoms and having a propylene content of 80.0 to 99.9% by weight, synthesized using Ziegler-Natta catalysts or metallocene catalysts in the form of random copolymers, block copolymers and/or random block copolymers with melt indexes of 0.1 to 50 g/10 minutes at 230xc2x0 C./2.16 kg and preferably of 0.2 to 15 g/10 minutes at 230xc2x0 C./2.16 kg are used. Particularly suitable for this purpose are propylene homopolymers, which have a bimodal distribution of molecular weights, weight average molecular weights MW of 500,000 to 1,500,000 g/mole, number average molecular weights Mn 25,000 to 100,000 g/mole and Mw/Mn values of 2 to 60 and were produced in a reactor cascade.
The largely amorphous polypropylenes or propylene copolymers B3), used for the synthesis of the co-continuous blends B are, in particular, stereo-block polypropylenes, which are synthesized, for example, using highly active metal oxide-fixed Ziegler-Natta catalysts (Collette, J., Macromolecules 22 (1989), 3851-3858, DE 28301601) or soluble Ziegler-Natta catalysts (de Candia, F., Makromol. Chem. 189(1988) 815-821), optionally with subsequent modification of the reactivity and/or degradation.
The non-isotactic propylene homopolymers B4), used for the synthesis of the co-continuous blends B, are products described in EP 475 307.
The ethylenically unsaturated, hydrolyzable organosilane compounds, present chemically bound in the co-continuous blends B, preferably are C3 to C8 alkenyl C1 to C2 alkoxy silanes, C2 to C14 alkenylhalogensilanes, amino C2 to C5 alkenylsilanes, C6 to C8 cycloalkenylsilanes, methacryloxy C1 to C3 alkylsilanes, styryl C1 to C2 alkoxysilanes, vinyl C1 to C4 alkoxysilanes and/or vinyl C1 to C8 carboxysilanes and especially vinyltrimethoxysilane and/or vinyltriethoxysilane.
The proportions of gel in the co-continuous blends B or the heterophasic polyolefin alloys was determined following the method of DIN 53 738 by extracting for 16 hours with hot xylene.
After a sample was taken from the middle region of the tensile test piece, the coefficient of thermal, longitudinal expansion was determined in each case along and at right angles to the injection direction. The experimental parameters were as follows: temperature 5xc2x0 to 95xc2x0 C., sample length about 7 mm, heating rate 3xc2x0 K./min, contacting force 0.02 N, contacting pressure 0.02 N/mm, flushing gas nitrogen.
The auxiliary materials, optionally contained in the heterophasic polyolefin alloys are 0.01 to 2.5% by weight of stabilizers, 0.1 to 1% by weight of antistatic agents, 0.2 to 3% by weight of pigments, 0.05 to 1% by weight of nucleating agents and/or 2 to 20% by weight of flame retardants, in each case based on the polyolefins used.
As stabilizers in the heterophasic polyolefin alloys, preferably mixtures of 0.01% to 0.6% by weight of phenolic antioxidants, 0.01% to 0.6% by weight of processing stabilizers based onphosphites, 0.01% to 0.6% by weight of 3-arylbenzofuranone derivatives, 0.01% to 0.6% by weight of high temperature stabilizers based on disulfides and thioethers and/or 0.01% to 0.8% by weight of sterically hindered amines (HALS), in each case based on the polyolefins used, may be contained.
Suitable phenolic antioxidants are 2-t-butyl-4,6-dimethylphenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-isoamylphenol, 2,6-di-t-butyl-4-ethylphenol, 2-t-butyl-4,6-diisopropylphenol, 2,6-dicyclopentyl-4-methylphenol, 2,6-di-t-butyl-4-methoxymethylphenol, 2-t-butyl-4,6-dioctadecylphenol, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-4,4-hexadecyloxyphenol, 2,2xe2x80x2-methylene-bis(6-t-butyl-4-methylphenol), 4,4xe2x80x2-thio-bis-(6-t-butyl-2-methylphenol), octadecyl 3(3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris(3xe2x80x2,5xe2x80x2-di-t-butyl-4-hydroxybenzyl)benzene and/or pentaerythritol-tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenyl)) propionate.
As HALS compounds, bis-2,2,6,6-tetramethyl-4-piperidyl sebacate and/or poly-((1,1,3,3-tetramethylbutyl)-imino)-1,3,5-triazine-2,4-diyl)(2,2,6,6-tetra-methylpiperidyl)-amino)-hexamethylene-4-(2,2,6,6-tetramethyl)piperidyl)-imino) are particularly suitable.
As processing aids, the heterophasic polyolefin alloys may preferably contain calcium stearate, magnesium stearate and/or waxes.
As nucleating agents, the heterophasic polyolefin alloys preferably may contain xcex1-nucleating agents, such as talcum or the sodium salt of methylene-bis(2,4-di-t-butylphenol) phosphoric acid or xcex2-nucleating agents, such as the dianilide of adipic acid, dibenzoquinacridone or N,Nxe2x80x2-dicyclohexyl-2,6-naphthalene dicarboxamide.
The fillers, optionally contained in the heterophasic polyolefin alloys, preferably are Al2O3, Al(OH)3, barium sulfate, calcium carbonate, glass spheres, wood flour, silica, hollow microspheres, carbon black, talcum and/or wollastonite.
The reinforcing materials, optionally contained in the heterophasic polyolefin alloys, preferably are aramide fibers, cellulose fibers, flax, jute, kenaf, glass fibers, glass mats, microfibers of liquid crystalline polymers and/or polytetrafluoroethylene fibers.
The heterophasic polyolefin alloys, with a semi-interpenetrating network structure and an outstanding combination of high stiffness, low temperature toughness and optionally a low coefficient of thermal expansion, of 65 to 99.6% by weight of propylene-polymers and 35 to 0.4% by weight of elastomeric polyolefins or styrene ethylene butadiene terpolymers and optionally 0.05 to 25% by weight of auxiliary materials and/or 10 to 70% by weight, in each case based on the sum of the polymers, of fillers and/or reinforcing materials are produced pursuant to the invention by melt compounding, 60 to 98% by weight of conventional propylene homopolymers or propylene copolymers A with 40 to 2% by weight of a co-continuous blend B, optionally with addition of 0.01 to 0.5% by weight of silanol condensation catalysts and/or 0.01 to 0.5% by weight of water, preferably with the continuous addition or propylene homopolymers or propylene copolymers to the co-continuous blends B, at temperatures of 120xc2x0 to 270xc2x0 C. and preferably of 200xc2x0 to 240xc2x0 C.,
wherein the co-continuous blends B on the basis of
B1) conventional propylene homopolymers or propylene copolymers with melt indexes ranging from 0.1 to 50 g/10 minutes at 230xc2x0 C./2.16 kg,
which are present in the mixture with 20 to 90% by weight of the elastomeric polyolefins or elastomeric styrene ethylene butadiene terpolymers,
B2) olefin copolymers of 50 to 95% by weight of ethylene and 50 to 5% by weight of propylene and/or xcex1-olefins with 4 to 18 carbon atoms and/or ethylenically unsaturated carboxylate esters of the vinyl acetate type and/or C1 to C8 alkyl (meth)acrylates with melt indexes of 0.2 to 30 g/10 minutes at 190xc2x0 C./2.16 kg, and/or
B3) largely amorphous polypropylenes or propylene copolymers with a crystalline polypropylenes or crystalline propylene copolymers content of less than 10% by weight, an enthalpy of melting of less than 40 J/g and a melt index of 0.1 to 40 g/10 minutes at 230xc2x0 C./2.16 kg, the elastomeric, largely amorphous polypropylene being a homopolymer of propylene and/or a copolymer of propylene of at least 80 mole percent propylene and not more than 20 mole percent of one or more xcex1-olefins of the general formula CH2xe2x95x90CHR, wherein R is a linear or branched alkyl group with 2 to 8 carbon atoms, and/or
B4) non-isotactic propylene homopolymers with a melting point of 145xc2x0 to 165xc2x0 C., a melt viscosity of 200,000 g/m/sec at 190xc2x0 C., a heat of crystallization of 4 to 10 cal/g and a solubility in diethyl ether of 35% by weight to 55% by weight, and/or
B5) linear styrene ethylene/butadiene styrene triblock copolymers with an ethylene content of 5 to 45% by weight and a styrene content of 15 to 45% by weight and a melt index of 0.2 to 30 g/10 minutes at 190xc2x0 C./2.16 kg,
1) either by the reaction of mixtures of 10 to 80% by weight of conventional propylene homopolymers or propylene copolymers and 90 to 20% by weight of elastomeric polyolefins or styrene ethylene butadiene terpolymers with 0.1 to 5.0% by weight of ethylenically unsaturated hydrolyzable organosilane compounds in the presence of 0.01 to 1.0% by weight of thermally decomposing free radical-forming agents with half-life times of 1 minute to 48 hours at 130xc2x0 C., 0.01 to 1.0% by weight of silanol condensation catalysts and optionally 0.01 to 1.0% by weight of water, in each case based on the elastomeric polyolefins or styrene ethylene butadiene terpolymers in continuous kneaders in the melt at temperatures of 120xc2x0 to 270xc2x0 C. and preferably of 200xc2x0 to 240xc2x0 C. and at pressures of 1 to 300 bar and preferably of 1 to 30 bar, at residence times of 0.5 to 40 minutes and preferably of 1 to 15 minutes,
2) or by the reaction of mixtures of 6 to 66% by weight of conventional propylene homopolymers or propylene copolymers and 94 to 33% by weight of elastomeric polyolefins or styrene ethylene butadiene terpolymers with 0.1 to 5.0% by weight, based on the elastomeric polyolefins or styrene ethylene butadiene terpolymers, of ethylenically unsaturated, hydrolyzable organosilane compounds in the presence of 0.01 to 1.0% by weight, based on the elastomeric polyolefins or styrene ethylene butadiene terpolymers, of thermally decomposing free radical-forming agents with half-life times of 1 minute to 48 hours at 130xc2x0 C. in the melt and the addition of a further 5 to 40% by weight, based on the polymer mixture, of conventional propylene homopolymers or propylene copolymers, and 0.01 to 1.0% by weight of silanol condensation catalysts and optionally 0.01 to 1.0% by weight of water, in each case based on the elastomeric polyolefins or styrene ethylene butadiene terpolymers, in continuous kneaders in the melt at temperatures of 120xc2x0 to 270xc2x0 C. and preferably of 200xc2x0 to 240xc2x0 C. and at pressures of 1 to 300 bar and preferably of 1 to 30 bar, at residence times of 0.5 to 40 minutes and preferably of 1 to 15 minutes,
3) or by the reaction of elastomeric polyolefins or styrene ethylene butadiene terpolymers with 0.1 to 5.0% by weight of ethylenically unsaturated, hydrolyzable organosilane compounds in the presence of 0.01 to 1.0% by weight, based on the elastomeric polyolefins or the styrene ethylene butadiene terpolymers, of thermally decomposing free radical-forming agents with half-life times of 1 minute to 48 hours at 130xc2x0 C. in continuous kneaders in the melt at temperatures of 120xc2x0 to 270xc2x0 C. and preferably of 200xc2x0 to 240xc2x0 C. and at pressures of 1 to 300 bar and preferably of 1 to 30 bar, at residence times of 0.5 to 40 minutes and preferably of 1 to 15 minutes, followed by granulation and subsequently by melt compounding of mixtures of 90 to 20% by weight of these modified, elastomeric polyolefins or styrene ethylene butadiene terpolymers and 10 to 80% by weight of conventional propylene homopolymers or propylene copolymers in the presence of 0.01 to 1.0% by weight of silanol condensation catalysts and optionally of 0.01 to 1.0% of water, based in each case on the elastomeric polyolefins or the styrene ethylene butadiene terpolymers, in continuous kneaders in the melt at temperatures of 120xc2x0 to 270xc2x0 C. and preferably of 200xc2x0 to 240xc2x0 C.,
0.01 to 2.5% by weight of stabilizers, 0.01 to 1% by weight of processing aids, 0.1 to 1% by weight of antistatic agents, 0.2 to 3% by weight of pigments, 0.05 to 1% by weight of nucleating agents and 2 to 20% by weight of flame retardants, in each case based on the sum of the polymers, being added as auxiliary materials, and/or 10 to 70% by weight and preferably 20 to 50% by weight, based on the sum of the polymers, of inorganic and/or organic fillers and/or reinforcing agents being added during the preparation of the co-continuous blend B and/or during the subsequent production of the heterophasic polyolefin alloys,
the conventional propylene homopolymers or propylene copolymers A and the conventional propylene homopolymers or propylene copolymers B1) being the same or different.
Preferably, single screw and twin-screw extruders, disk extruders and calenders are suitable as continuous kneaders.
Thermally decomposing free radical-forming agents preferably used for the preparation of co-continuous blends B, are peroxides, which have a half-life time of 30 seconds to 3 minutes at a temperature of 180xc2x0 to 200xc2x0 C., especially dicumyl peroxide, cumyl t-butyl peroxide, di-t-butyl peroxide and/or 2,5-dimethyl-2,5-(di-t-butyl peroxy)-hexane.
As silanol condensation catalysts for the production of co-continuous blends B and optionally of the heterophasic polyolefin alloys, preferably oxides, hydroxides and/or carboxylic acid salts of the metals tin, titanium, zinc, zirconium, iron, copper and/or lead are used, dibutyl tin dilaurate, dibutyl tin dioctoate and/or C1 to C12 dialkyl tin oxides being particularly preferred. During the production of the co-continuous blend B, the absorption of the silanol condensation catalysts brings about an excellent preliminary distribution of the thermally decomposing free radical-forming agent and of the ethylenically unsaturated hydrolyzable organosilane compounds.
A preferred method of adding the ethylenically unsaturated, hydrolyzable organosilane compounds, free radical-forming agents and silanol condensation catalysts used consists therein that these components are drummed in internal mixers, such as Rxc3x6hnrad mixers, onto the elastomeric polyolefins or the styrene ethylene butadiene terpolymers.
The gel formation in the co-continuous blends can be accelerated by the addition of slight amounts of water, particularly by the addition of moistened polypropylene by side stream addition.
In a preferred variation of the method of producing heterophasic polyolefin blends, the production of the co-continuous blend B and the subsequent preparation of the heterophasic polyolefin alloys are carried out in an extruder cascade of 2 twin-screw extruders, particularly of tightly meshing twin-screw extruders rotating in the same direction, as a continuous kneader, in a first extruder, at mass temperatures of 190xc2x0 to 250xc2x0 C., mixtures of propylene homopolymers or propylene copolymers, elastomeric polyolefins or styrene ethylene butadiene terpolymers and ethylenically unsaturated, hydrolyzable organosilane compounds being reacted, the propylene homopolymers or propylene copolymers optionally being added to the co-continuous blend B as a side stream, and subsequently, in the second extruder, the heterophasic polyolefin alloys being produced by homogenizing the co-continuous blend B with an excess of propylene homopolymers or propylene copolymers, optionally with the addition of 0.01 to 0.5% by weight of silanol condensation catalysts and/or 0.01 to 0.5% by weight of water, at mass temperatures of 190xc2x0 to 250xc2x0 C. at high deformation speeds.
A further preferred variation of the method for producing heterophasic polyolefin alloys consists therein that the production of the co-continuous blends B and the subsequent production of the heterophasic polyolefin alloys is carried out in a twin-screw extruder with an L/D of 32 to 60 and preferably in a tightly meshing twin-screw extruder, rotating in the same direction, with an L/D of 40 to 60, the reaction of the mixtures of propylene homopolymers or propylene copolymers, elastomeric polyolefins or styrene ethylene butadiene terpolymers and ethylenically unsaturated, hydrolyzable organosilane compounds to the co-continuous blends B being carried out in the first 50 to 75% of the process length of the extruder components and the production of the heterophasic polyolefin alloys by homogenizing the co-continuous blends B with an excess of propylene homopolymers or propylene copolymers A, with side stream addition of the propylene homopolymers or the propylene copolymers A, optionally with the addition of 0.01 to 0.5% by weight of silanol condensation catalysts and/or 0.01 to 0.5% by weight of water, being carried out in the final 25 to 50% of the process length of the extruder components.
The heterophasic polyolefin alloys are suitable, in particular for the production of films, sheets, fibers, panels, coatings, injection molded articles, pipes, hollow objects and foams.